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Sputum Glucose and Glycemic Control in Cystic Fibrosis-Related Diabetes: A Cross-Sectional Study

Van Sambeek, Lindsey and Cowley, Elise S. and Newman, Dianne K. and Kato, Roberta (2015) Sputum Glucose and Glycemic Control in Cystic Fibrosis-Related Diabetes: A Cross-Sectional Study. PLoS ONE, 10 (3). Art. No. e0119938. ISSN 1932-6203. PMCID PMC4372582.

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Cystic fibrosis-related diabetes affects up to half of cystic fibrosis patients and is associated with increased mortality and more frequent pulmonary exacerbations. However, it is unclear to what degree good glycemic control might mitigate these risks and clinical outcomes have not previously been studied in relation to glucose from the lower airways, the site of infection and CF disease progression. We initially hypothesized that diabetic cystic fibrosis patients with glycosylated hemoglobin (HbA_(1c)) > 6.5% have worse pulmonary function, longer and more frequent exacerbations and also higher sputum glucose levels than patients with HbA_(1c) ≤ 6.5% or cystic fibrosis patients without diabetes. To test this, we analyzed spontaneously expectorated sputum samples from 88 cystic fibrosis patients. The median sputum glucose concentration was 0.70 mM (mean, 4.75 mM; range, 0-64.6 mM). Sputum glucose was not correlated with age, sex, body mass index, diabetes diagnosis, glycemic control, exacerbation frequency or length, or pulmonary function. Surprisingly, sputum glucose was highest in subjects with normal glucose tolerance, suggesting the dynamics of glycemic control, sputum glucose and pulmonary infections are more complex than previously thought. Two-year mean HbA_(1c) was positively correlated with the length of exacerbation admission (p < 0.01), and negatively correlated with measures of pulmonary function (p < 0.01). While total number of hospitalizations for exacerbations were not significantly different, subjects with an HbA_(1c) > 6.5% were hospitalized on average 6 days longer than those with HbA_(1c) ≤ 6.5% (p < 0.01). Current clinical care guidelines for cystic fibrosis-related diabetes target HbA_(1c) ≤ 7% to limit long-term microvascular damage, but more stringent glycemic control (HbA_(1c) ≤ 6.5%) may further reduce the short-term pulmonary complications.

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Van Sambeek, Lindsey0000-0002-7206-7410
Newman, Dianne K.0000-0003-1647-1918
Additional Information:© 2015 Van Sambeek et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received: June 26, 2014; Accepted: January 31, 2015; Published: March 24, 2015. Academic Editor: Konstantinos Kostikas, University of Athens Medical School, GREECE. This work is supported by the Heart, Lung and Blood Institute of the National Institutes of Health (, grant number R01HL117328 and the Del E. Webb Grant Foundation ( DKN is an Investigator of the Howard Hughes Medical Institute. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We would like to thank Dr. Kyle McCallin, Carmen Reyes, Lynn Fukushima, Michelle Gonzalez and Pooja Patel for assistance in collecting samples and Drs. Megan Bergkessel and Adupa Rao for their helpful discussions. Author Contributions: Conceived and designed the experiments: LVS DKN RK. Performed the experiments: LVS ESC. Analyzed the data: LVS RK. Contributed reagents/materials/analysis tools: LVS ESC DKN RK. Wrote the paper: LVS ESC DKN RK. Acquired clinical samples: ESC. Competing interests: The authors have declared that no competing interests exist. Data Availability: All relevant data are within the paper and its Supporting Information files.
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Del E. Webb FoundationUNSPECIFIED
Howard Hughes Medical Institute (HHMI)UNSPECIFIED
Issue or Number:3
PubMed Central ID:PMC4372582
Record Number:CaltechAUTHORS:20150604-131000659
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Official Citation:Van Sambeek L, Cowley ES, Newman DK, Kato R (2015) Sputum Glucose and Glycemic Control in Cystic Fibrosis-Related Diabetes: A Cross-Sectional Study. PLoS ONE 10(3): e0119938. doi:10.1371/journal.pone.0119938
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:58004
Deposited By: George Porter
Deposited On:04 Jun 2015 20:27
Last Modified:09 Mar 2020 13:19

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